This invention relates generally to ordnance fuzes, and, more particularly to a time delay mechanism capable of delaying the detonating action of a fuze utilized within a projectile.
It becomes necessary in many instances to destroy or disarm thin skinned material targets such as aircraft or the like which are capable of surviving the explosive force of most conventional weapons. There are two basis elements which must be considered in defeating such a target. First, it is necessary for the housing of the projectile to be of sufficient strength to pierce the protective shield of the target and second, the explosive action of the projectile must be capable of destroying the components located behind the skin of the target after such perforation. Merely punching a hole in the skin, in many instances, does not constitute a defeat or disablement of the aircraft.
Antiaircraft missiles or projectiles will generally detonate upon impact with the target such as an airplane, generally causing damage to the external configuration of the aircraft without doing substantial damage to the interior thereof. It is therefore desirable to incorporate in anti aircraft projectiles and the like a delay which will permit the missile to penetrate the target before the main explosive charge is detonated thereby effecting maximum damage to the target.
The fuze is the mechanism utilized for igniting or detonating the bursting charge of such a projectile and performs this function upon impact of the projectile with any substantially rigid object, or in the case of a delay action fuze, at a predetermined time thereafter. Fuzes should be safe in handling and usage, free from deterioration in storage, simple in design and operation and easy to manufacture and load.
The desired delay time which is necessary in the anti aircraft missiles or projectiles as set forth hereinabove is in the order of 0.25 milliseconds. Mechanical delay devices can produce the desired delay under certain conditions but the delay time is a direct function of striking velocity, target thickness, target density and impact angles. Pyrotechnic delays are useful for long delay times but are unreliable for the short times set forth hereinabove. It is therefore essential to produce a fuze which not only is capable of a millisecond delay period but which also meets the fuze criteria as set forth hereinabove.